Discovery of Undescribed Monoterpenoid Polyprenylated Acylphloroglucinols with Immunosuppressive Activities from Hypericum longistylum

Abstract

Acylphlorostylums A-G (1-7), seven undescribed monoterpenoid polyprenylated acylphloroglucinols, were isolated and identified from Hypericum longistylum. Significantly, acylphlorostylums A and B were the first monoterpenoid polyprenylated acylphloroglucinols possessing a dodecahydro-1H-benzo [b]cyclopenta [e]oxepine moiety bearing a 6/7/5 fused tricyclic ring system that assembled by the attack from 4-OH to C-13. In addition, acylphlorostylums A-G exhibited moderate in vitro immunosuppressive activity in anti-CD3/anti-CD28 monoclonal antibodies, lipopolysaccharide and concanavalin A-induced murine splenocyte proliferation, with IC₅₀ values ranging from 1.51 ± 0.12 to 18.49 ± 1.67 μM, underscoring those isolates as novel chemical templates in the development of novel immunosuppressors.

Keywords: Chemical calculation; Clusiaceae; Hypericum longistylum; Immunosuppressive activity; Monoterpenoid polyprenylated acylphloroglucinols; Structural elucidation.